1. Field of the Invention
The present invention relates to a sensor including a photoelectric conversion element and a method for controlling the sensor.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. 2007-74421 discusses a sensor which includes a pixel array 1a, in which pixels that generate signal charges by photoelectric conversion are arranged, also includes a storage gate 3a, which stores a signal charge that has been generated in a pixel array.
In addition, Japanese Patent Application Laid-Open No. 2009-060598 discusses a method for executing a control for discharging an unnecessary charge, which has been stored on a charge storage unit configured to store a signal charge, to suppress an affect from the unnecessary charge.
While transferring a signal charge to the outside of a sensor, the charge storage unit stores a charge (signal charge) of an image. Accordingly, if the charge of the image is stored by the charge storage unit for a long time, a noise (dark current noise (charge)), which may occur due to the dark current, may be added to the signal charge. As a result, the noise may occur on the image signal input by the sensor. The noise is approximately proportional to the temperature and the storage time.
The method discussed in Japanese Patent Application Laid-Open No. 2009-060598 can discharge an unnecessary charge after a charge of an image is externally transferred but cannot discharge an unnecessary charge after a noise is added to an image by the charge storage unit.